This invention is in the field of maize breeding. Specifically, this invention relates to a novel corn hybrid having the designation P741.
Principles of conventional plant breeding Most of the commercial corn produced in the United States is produced from hybrid seed. The production of hybrid seed first requires the development of elite corn inbred lines that possess good combining ability to produce agronomically superior hybrids. The majority of hybrid seed produced in the United States is of the single cross type, wherein two inbred lines are intermated, or crossed, to produce what is termed seed of an F1 single cross hybrid. This seed is then sold to commercial grain growers who plant the seed and harvest the second generation, or F2 grain, for use on farm or for commercial sale.
The production of conventional single cross hybrid seed involves controlling the direction of pollination from one inbred to the other to assure the production of predominantly hybrid (cross pollinated) seed. Typically, directed pollination is accomplished by interplanting separate rows of female corn plants with male corn plants. The female corn plants that are male sterile may be produced by genetic mechanisms which render the corn tassel or pollen nonfunctional or by detasseling the plants in the field.
The development of corn hybrids requires the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Pedigree breeding, backcross conversion and recurrent selection breeding methods are used to develop the inbred lines from breeding populations. These breeding methods combine desirable traits from two or more inbred lines or various broad-based populations into breeding pools from which new inbred lines are developed by inbreeding or random mating and selection of desired phenotypes. The new inbreds are crossed with other inbreds and the resulting hybrids are evaluated to determine which have commercial value and agronomic usefulness.
The objective of typical plant breeding is to develop a hybrid with desirable traits such as resistance to diseases and insects, herbicide tolerance, tolerance to heat and drought, reduction of time to crop maturity, and improved agronomic quality. Because many crops are harvested mechanically, uniformity of plant characteristics such as germination time, stand establishment, growth rate, and fruit/seed size are also desirable.
The problem with conventional breeding techniques is that there are several grain quality traits, such as high oil content, that cannot readily be obtained in a high-yielding single cross hybrid. One solution to this problem has been proposed by Bergquist et al. in U.S. Pat. Nos. 5,704,160 and 5,706,603, incorporated herein by reference. A primary aspect of this method, known as the TOPCROSS(copyright) grain production system, is the interplanting of a pollinator corn plant possessing the characteristics for significantly increasing oil level in the resulting grain, with a male sterile hybrid corn plant. The resulting grain possesses an oil content much higher than would be expected for self- or cross-pollination of the fertile version of the hybrid corn plant.
In practice, the seed of the pollinator with improved grain quality traits is blended in small amounts with seed of an elite male sterile grain parent hybrid, but with sufficient pollinator seed to permit abundant pollen production for fertilization of the male sterile grain parent hybrid. The relatively low ratio of pollinator seed to male sterile grain parent seed (typically less than one pollinator plant to every three grain parent plants) takes advantage of the higher grain yield potential of the elite grain parent hybrid while assuring a sufficient population of pollinator plants to pollinate the male sterile grain parent plants.
Critical to the success of the TOPCROSS(copyright) grain production system is the use of a pollinator capable of enhancing the grain quality traits of the F1 grain. P741 was developed for this purpose. The present invention, when used as a pollinator, imparts high oil content accompanied by high test weight to the resulting F1 grain without significant loss of yield.
According to the invention, there is provided a novel corn hybrid, designated P741, that when used to pollinate an elite male sterile hybrid grain parent, produces commercial grain exhibiting improved quality grain traits, including high oil along with good test weight.
P741 is a medium-late flowering synthetic hybrid, broadly adapted to the corn growing areas of the Central United States. Grain from P741 has expressed high oil and excellent test weight.
The invention thus relates to the seeds, plants and plant parts of P741; to tissue culture comprising regenerable cells of a plant part of P741; to plants regenerated from regenerable cells of the tissue culture of P741; to corn plants having substantially all the phenotypic, genotypic and/or physiological characteristics of P741; to the method of producing P741; to grain or seed produced by crossing P741 with a different corn plant wherein the resulting progeny have one-half the nuclear genotype of P741; to seed blends of P741 and male sterile corn hybrids; to a method of producing high oil grain using P741 as a pollinator in a TC BLEND(copyright) seed mixture; and to corn plants produced or derived from P741 seed wherein the corn plants have the ability to impart high oil or other grain quality traits to the F1 grain when these P741-derivatives are used in the TOPCROSS(copyright) grain production system.
In the description that follows, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided:
Combining Ability. The ability of a genetic strain, when crossed with another strain, to produce a high proportion of desirable individuals.
Endosperm. The nutritive tissue formed within the embryo sac in seed plants. It commonly arises following the fertilization of the diploid polar nucleus by one male sperm.
Express. To manifest a genetic character trait.
F1. The first generation of a cross.
F2. The second filial generation obtained by self-fertilization or crossing inter se of F1 individuals. Subsequent generations are F3, F4, F5, etc.
Genotype. The fundamental genetic constitution of an organism.
Grain. Mature corn kernels produced by commercial growers for purposes other than growing or reproducing the species.
Grain Parent. Male sterile, elite hybrid that comprises a large majority of the plants in a grain production field.
Grain Quality Trait. Any attribute of grain that is of commercial value. Such traits relate to the intermediate or final use of grain and include but are limited to the quantity or quality of oil, protein, starch, pigmentation, and fiber found in corn grain. Such traits also encompass physical attributes of the grain itself, such as grain texture, size, or hardness, among others. Certain of these compositional or physical attributes of grain correlate with functional attributes as well which are of commercial importance, such as susceptibility to breakage and spoilage, among others.
Homozygous. A genetic condition existing when identical alleles reside at corresponding loci on homologous chromosomes.
Hybrid. (1) The progeny of a cross fertilization between parents belonging to different genotypes. (2) The first generation offspring of a cross between two individuals differing in one or more genes. (3) A hybrid is the result of a cross between two or more components.
Inbred or Inbred Line. A substantially homozygous individual, variety or line produced by continued inbreeding. In plant breeding a nearly homozygous line usually originates by continued self-fertilization, accompanied by selection.
Kernel. The corn caryopsis comprising a mature embryo and endosperm which are products of double fertilization.
Line. (1) A group of individuals from a common ancestry. (2) A narrowly defined group that is a variety.
Male Sterile. A condition in which pollen is absent or non-functional in flowering plants.
Percent Oil. The oil concentration of a corn kernel, typically determined at 0% moisture.
Phenotype. (1) Physical or external appearance of an organism as contrasted with its genetic constitution (=genotype); (2) a group of organisms with similar physical or external makeup; (3) the observed character of an individual without reference to its genetic nature.
Pollen. A structure which gives rise to two haploid sperm nuclei which fuse with the egg nucleus and polar nuclei found in the ovule to give rise to the embryo and endosperm of the mature corn kernel.
Pollinators. Male fertile corn plants used to pollinate male sterile hybrid corn plants in order to produce a Grain Quality Trait in the resulting F1 grain.
Population. In genetics, a community of individuals which share a common gene pool.
Seed. Mature corn kernels produced for the purpose of propagating the species.
Single Cross. A cross between two different genotypes, each of which may be an inbred or synthetic.
Synthetic (Population). A genetically heterogeneous collection of plants of known ancestry created by the intermating of any combination of inbreds, hybrids, varieties, populations, races or other synthetics.
Synthetic Hybrid. A hybrid in which one or more genotypes used to make the hybrid is a synthetic.
TC BLEND(copyright). A registered trademark of E.I. duPont de Nemours and Company for a physical mixture of two or more types of seed utilized in the TOPCROSS(copyright) grain production system.
Test Weight. The measure of the weight of the grain in pounds for a given volume (bushel) adjusted for percent moisture at harvest.
TOPCROSS(copyright). A registered trademark of E.I. duPont de Nemours and Company for a grain production system and the high oil corn seed used therein.
Yield (Bushels/Acre). The yield in bushels/acre is the actual yield of the grain at harvest adjusted to 15.5% moisture. One bushel is equal to 56 pounds.